/*
 * Copyright (c) 1996, 2005, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.sql;

/**
 * An object that can be used to get information about the types
 * and properties of the columns in a <code>ResultSet</code> object.
 * The following code fragment creates the <code>ResultSet</code> object rs,
 * creates the <code>ResultSetMetaData</code> object rsmd, and uses rsmd
 * to find out how many columns rs has and whether the first column in rs
 * can be used in a <code>WHERE</code> clause.
 * <PRE>
 *
 * ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2");
 * ResultSetMetaData rsmd = rs.getMetaData();
 * int numberOfColumns = rsmd.getColumnCount();
 * boolean b = rsmd.isSearchable(1);
 *
 * </PRE>
 */

public interface ResultSetMetaData extends Wrapper {

  /**
   * Returns the number of columns in this <code>ResultSet</code> object.
   *
   * @return the number of columns
   * @throws SQLException if a database access error occurs
   */
  int getColumnCount() throws SQLException;

  /**
   * Indicates whether the designated column is automatically numbered.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return <code>true</code> if so; <code>false</code> otherwise
   * @throws SQLException if a database access error occurs
   */
  boolean isAutoIncrement(int column) throws SQLException;

  /**
   * Indicates whether a column's case matters.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return <code>true</code> if so; <code>false</code> otherwise
   * @throws SQLException if a database access error occurs
   */
  boolean isCaseSensitive(int column) throws SQLException;

  /**
   * Indicates whether the designated column can be used in a where clause.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return <code>true</code> if so; <code>false</code> otherwise
   * @throws SQLException if a database access error occurs
   */
  boolean isSearchable(int column) throws SQLException;

  /**
   * Indicates whether the designated column is a cash value.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return <code>true</code> if so; <code>false</code> otherwise
   * @throws SQLException if a database access error occurs
   */
  boolean isCurrency(int column) throws SQLException;

  /**
   * Indicates the nullability of values in the designated column.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return the nullability status of the given column; one of <code>columnNoNulls</code>,
   * <code>columnNullable</code> or <code>columnNullableUnknown</code>
   * @throws SQLException if a database access error occurs
   */
  int isNullable(int column) throws SQLException;

  /**
   * The constant indicating that a
   * column does not allow <code>NULL</code> values.
   */
  int columnNoNulls = 0;

  /**
   * The constant indicating that a
   * column allows <code>NULL</code> values.
   */
  int columnNullable = 1;

  /**
   * The constant indicating that the
   * nullability of a column's values is unknown.
   */
  int columnNullableUnknown = 2;

  /**
   * Indicates whether values in the designated column are signed numbers.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return <code>true</code> if so; <code>false</code> otherwise
   * @throws SQLException if a database access error occurs
   */
  boolean isSigned(int column) throws SQLException;

  /**
   * Indicates the designated column's normal maximum width in characters.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return the normal maximum number of characters allowed as the width of the designated column
   * @throws SQLException if a database access error occurs
   */
  int getColumnDisplaySize(int column) throws SQLException;

  /**
   * Gets the designated column's suggested title for use in printouts and
   * displays. The suggested title is usually specified by the SQL <code>AS</code>
   * clause.  If a SQL <code>AS</code> is not specified, the value returned from
   * <code>getColumnLabel</code> will be the same as the value returned by the
   * <code>getColumnName</code> method.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return the suggested column title
   * @throws SQLException if a database access error occurs
   */
  String getColumnLabel(int column) throws SQLException;

  /**
   * Get the designated column's name.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return column name
   * @throws SQLException if a database access error occurs
   */
  String getColumnName(int column) throws SQLException;

  /**
   * Get the designated column's table's schema.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return schema name or "" if not applicable
   * @throws SQLException if a database access error occurs
   */
  String getSchemaName(int column) throws SQLException;

  /**
   * Get the designated column's specified column size. For numeric data, this is the maximum
   * precision.  For character data, this is the length in characters. For datetime datatypes, this
   * is the length in characters of the String representation (assuming the maximum allowed
   * precision of the fractional seconds component). For binary data, this is the length in bytes.
   * For the ROWID datatype, this is the length in bytes. 0 is returned for data types where the
   * column size is not applicable.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return precision
   * @throws SQLException if a database access error occurs
   */
  int getPrecision(int column) throws SQLException;

  /**
   * Gets the designated column's number of digits to right of the decimal point.
   * 0 is returned for data types where the scale is not applicable.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return scale
   * @throws SQLException if a database access error occurs
   */
  int getScale(int column) throws SQLException;

  /**
   * Gets the designated column's table name.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return table name or "" if not applicable
   * @throws SQLException if a database access error occurs
   */
  String getTableName(int column) throws SQLException;

  /**
   * Gets the designated column's table's catalog name.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return the name of the catalog for the table in which the given column appears or "" if not
   * applicable
   * @throws SQLException if a database access error occurs
   */
  String getCatalogName(int column) throws SQLException;

  /**
   * Retrieves the designated column's SQL type.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return SQL type from java.sql.Types
   * @throws SQLException if a database access error occurs
   * @see Types
   */
  int getColumnType(int column) throws SQLException;

  /**
   * Retrieves the designated column's database-specific type name.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return type name used by the database. If the column type is a user-defined type, then a
   * fully-qualified type name is returned.
   * @throws SQLException if a database access error occurs
   */
  String getColumnTypeName(int column) throws SQLException;

  /**
   * Indicates whether the designated column is definitely not writable.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return <code>true</code> if so; <code>false</code> otherwise
   * @throws SQLException if a database access error occurs
   */
  boolean isReadOnly(int column) throws SQLException;

  /**
   * Indicates whether it is possible for a write on the designated column to succeed.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return <code>true</code> if so; <code>false</code> otherwise
   * @throws SQLException if a database access error occurs
   */
  boolean isWritable(int column) throws SQLException;

  /**
   * Indicates whether a write on the designated column will definitely succeed.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return <code>true</code> if so; <code>false</code> otherwise
   * @throws SQLException if a database access error occurs
   */
  boolean isDefinitelyWritable(int column) throws SQLException;

  //--------------------------JDBC 2.0-----------------------------------

  /**
   * <p>Returns the fully-qualified name of the Java class whose instances
   * are manufactured if the method <code>ResultSet.getObject</code>
   * is called to retrieve a value
   * from the column.  <code>ResultSet.getObject</code> may return a subclass of the
   * class returned by this method.
   *
   * @param column the first column is 1, the second is 2, ...
   * @return the fully-qualified name of the class in the Java programming language that would be
   * used by the method <code>ResultSet.getObject</code> to retrieve the value in the specified
   * column. This is the class name used for custom mapping.
   * @throws SQLException if a database access error occurs
   * @since 1.2
   */
  String getColumnClassName(int column) throws SQLException;
}
